return to home page Computational Chemistry Comparison and Benchmark DataBase Release 19 (April 2018) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Calculated > Vibrations > Bad Calculations > Bad vib. Calc. vs exp. OR Resources > Bad Calculations > Vibrations > Bad vib. Calc. vs exp.

Bad vibrational frequency predictions

Calculated frequencies that differ from experiment by more than 400 cm-1 or have a ratio with experiment outside of 0.7 to 1.2 are listed

Calculated vibrational frequencies ("theory" in table) are calculated at MP2=FULL/6-31G(2df,p)
Calculated values were scaled by 0.9423.

Species Name mode Symmetry Experiment Theory difference ratio
CH3SeH Methane selenol 12 A" 145 228 83 0.635
CH3CONH2 Acetamide 20 A 259 185 -74 1.400
CH3OH Methyl alcohol 12 A" 200 319 119 0.627
C2H4+ Ethylene cation 4 Au 84 -119 -203 -0.705
C2H2 Acetylene 4 Πg 612 477 -135 1.284
HCN+ hydrogen cyanide cation 1 Σ 3050 3531 481 0.864
HCN+ hydrogen cyanide cation 2 Σ 1800 2704 904 0.666
CHONH2 formamide 12 A" 289 98 -191 2.955
CBr2F2 Methane, dibromodifluoro- 9 B2 235 337 102 0.698
C3F8 perfluoropropane 13 A2 276 214 -62 1.292
C3H6O 2-Propen-1-ol 24 A 188 108 -81 1.749
CH2NN diazomethane 6 B1 406 131 -275 3.093
NH2CN cyanamide 5 A' 408 634 226 0.644
C4H6O2 2,3-Butanedione 21 Bg 240 127 -113 1.896
C3H6O Oxetane 18 B1 90 -77 -166 -1.173
CO+ carbon monoxide cation 1 Σ 2214 2692 478 0.822
C6H6 Benzvalene 10 A1 996 738 -258 1.350
C2F2 difluoroacetylene 4 Πg 270 453 183 0.596
H2CS- thioformaldehyde anion 4 B1 450 -155 -605 -2.904
SiF2+ Silicon difluoride cation 2 A1 350 269 -81 1.300
C5H8 1,3-Pentadiene, (Z)- 22 A' 144 212 68 0.681
C5H8 1,3-Pentadiene, (Z)- 31 A" 456 343 -113 1.329
CN Cyano radical 1 Σ 2069 2728 660 0.758
C2H Ethynyl radical 2 Σ 1841 2388 547 0.771
C2H Ethynyl radical 3 Π 372 823 452 0.451
C2H+ Ethynyl cation 3 Π 550 810 260 0.679
CH3 Methyl radical 2 A2" 606 372 -234 1.629
CH2OH Hydroxymethyl radical 8 A 482 693 211 0.696
CH2OH Hydroxymethyl radical 9 A 234 431 197 0.543
HCCN cyanomethylene 4 Π 383 551 168 0.696
HCCN cyanomethylene 5 Π 129 -315 -444 -0.409
CHCl2 dichloromethyl radical 4 A' 190 296 106 0.642
CH2CHO Vinyloxy radical 10 A" 703 1028 325 0.684
O2+ diatomic oxygen cation 1 Σg 1906 1422 -484 1.340
GaF3 Gallium trifluoride 4 E' 192 93 -99 2.062
CaF2 Calcium difluoride 2 A1 120 84 -36 1.428
O3 Ozone 3 B2 1042 2076 1034 0.502
NO Nitric oxide 1 Σ 1904 3193 1289 0.596
NO2 Nitrogen dioxide 3 B2 1618 4523 2905 0.358
N2O3 Dinitrogen trioxide 9 A" 63 169 106 0.372
C3O Tricarbon monoxide 5 Π 109 164 55 0.664
VO Vanadium monoxide 1 Σ 1011 1915 903 0.528
C3 carbon trimer 3 Πu 63 218 154 0.291
SiP Silicon monophosphide 1 Σ 616 1011 396 0.609
Cu2 Copper dimer 1 Σg 265 417 153 0.634
PS phosphorus sulfide 1 Σ 739 1063 324 0.695
PN+ phosphorus nitride cation 1 Σ 1200 1607 407 0.747
OPCl Phosphorus oxychloride 2 A' 308 487 179 0.632
OPCl Phosphorus oxychloride 3 A' 492 288 -204 1.706
H2OH2O water dimer 12 A" 88 50 -38 1.756
H2POH Phosphinous acid 9 A" 375 264 -111 1.419
ZnCH3 Zinc monomethyl 6 E 315 598 283 0.527
ONONO Nitrosyl nitrite 9 B2 380 298 -82 1.274